Tool for a row cultivator, having a leading blade and cutting blades

ABSTRACT

A row cultivator (10) includes a row following system (12) coupled to a toolbar (13) employing frame members (17) and (18) constrained to remain parallel by a cross member (21). Coulter wheels (30) and (31) secured to the frame members (17) and (18) are non-steerable and tool bar drift may be corrected. A tool (40) employs a leading blade (44) and a pair of diverging cutting blades (47) and (48) trailing behind the leading blade (44). A sheer release assembly employs a longitudinally extending bolt (70) centrally disposed and holding a shank (61) to a tool bar (65) so that when a tool on the shank (61) strikes an underground obstacle the bolt (70) is sheared longitudinally.

This application is a division of application No. 08/361,053, filed Dec.21, 1994, now allowed as U.S. Pat. No. 5,603,380.

THIS INVENTION relates to improvements in or in relation to rowcultivators.

BACKGROUND OF THE INVENTION

At present, row cultivators suffer from a number of disadvantages.

One disadvantage arises where a large number of rows are being workedand a guidance system is employed to account for tool bar drift. Atpresent, guidance systems employ probes which track the crop or thebottom of the furrow between adjacent rows. Coulter wheels on theguidance system are steered in response to detected deviation of theprobe and forward travel is required to obtain a correction. Therefore,existing guidance systems have a slow response time and it would bedesirable to provide an improved guidance system with improved responsetime.

Another disadvantage arises where cutter blades are employed behind atool. Typical tooling for cultivating row crops consist of five verticalshank assemblies per row of crop with a tool comprising either "L"shaped knives or a single disc attached to the end of the shank. Eachtool's position can be independently adjusted vertically andhorizontally.

The main problems with this type of arrangement are:

(i) the difficulty in adjusting the shank assemblies; and

(ii) the narrow knives or discs allow weeds to bend around the toolingif the weed is not struck "dead-centre".

The present cutter blade arrangements are inefficient.

A further disadvantage arises with present shear release arrangementsfor shear release of shanks. At present under existing shear releasearrangements where a tool strikes an underground obstacle such as a rockor root, a horizontally extending transverse bolt is sheared and theshank swings backward about a transversely extending horizontal pivot.After this happens, repair is a very time consuming process because whenthe bolt is sheared, it does not shear cleanly and removal of the boltis difficult resulting in a long period of down time for the cultivator.

SUMMARY OF THE INVENTION

The applicant has devised a number of improvements which alleviate theabove problems and although the improvements can be used independently,it is preferable to use the improvements in combination for the overallbenefit they provide.

In one aspect therefore, the present invention is directed to a rowfollowing system for a row cultivator of the type employing a transversetool bar carrying cultivating tools behind a prime mover, the rowfollowing system being responsive to transverse deviation of the toolbar from a desired position and being operative to return the tool barto the desired position, the improvement comprising a pair of parallelspaced frame members trailing behind and pivotally coupled to the toolbar at transversally spaced apart locations to pivot in concert aboutspaced vertical axes, a cross member bridging between the frame membersand having opposite ends pivotally coupled to the frame members to pivotabout vertical pivot axes, a coulter wheel attached to each framemember, each coulter wheel rotating about a fixed horizontal axis andthere being provided frame member drive means adapted to push the framemembers relative to the cross member whenever the tool bar drifts from adesired position so that the tool bar position is thereby corrected. Thecoulter wheels are preferably fixed and parallel to the frame members.

The spaced frame members can be any form. Each frame member preferablyincludes respective dog leg sections behind the respective verticalpivot connections to the cross member, the dog leg sections positioningthe coulter wheels outside the frame members, the frame members havingprojecting end portions projecting back behind the cross member and thedrive means comprising respective double acting hydraulic cylinderassemblies bridging between opposite ends of the cross member and therespective projecting end portions of the frame members.

In another aspect, the present application is directed to a tool for arow cultivator, the tool having a shank fitted with a leading blade forworking soil, the leading blade being followed by a pair of cuttingblades adapted to travel just below soil level to sever weeds on eitherside of the leading blade, the cutting blades having respective leadingedges diverging rearwardly and outwardly on opposite sides of theleading blade.

The tool preferably includes a blade carrier unit secured to the shank,the carrier unit having a forward leading blade attachment means and arearward cutting blade attachment means, the rearward cutting bladeattachment means preferably comprising a pair of spaced vertical platesreceiving a cutting blade carrier unit in the form of an invertedgenerally T-shaped plate.

Each cutting blade is preferably tapered, having a broad forward cuttingedge portion located behind and inside the periphery of the leadingblade.

Each cutting blade preferably has a forward portion located within theshadow of the leading blade.

In a further aspect, the present application provides a shear releaseassembly for a shank of a row cultivator being of the type employing ashank having a lower end carrying a tool traveling forward in soil andan upper end, the upper end being pivotally connected to a tool bar andbeing secured against pivot by the shear release assembly, the shearrelease assembly comprising a shear fastener holding the shank againstpivot by applying a fastening force disposed in the direction of travelof said shank and at right angles to the shank pivot axis so that whenthe shank encounters an underground obstacle, the fastening force isovercome to shear the fastener and release the shank.

The shank is typically held in a clamping frame having spaced framemembers coupled to the pivot, the clamping frame having a forwardportion located below the pivot, the forward portion holding the shearfastener so that the forward portion separates from the support frame torelease the shank when the tool encounters an underground obstacle.

The fastener is preferably centrally disposed relative to the clampingframe so that the fastener is centrally located on a central planethrough which maximum force is applied.

In order that the present improvements can be more readily understoodand be put into practical effect, reference will now be made to theaccompanying drawings and wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a row cultivator employing a row followingsystem according to the present improvements;

FIG. 2 is schematic plan view illustrating the operation of a typicalrow following system according to the present improvements;

FIGS. 2 and 3 are respective plan and side views of a preferred toolemploying a leading blade and cutting blades according to the presentimprovements; and

FIGS. 3, 4, 5, 6, and 7, are side and cut away part views illustratingoperation of a shear release assembly according to a preferred form ofthe present improvements.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings and initially to FIGS. 1 and 2, there isillustrated a row cultivator 10 articulated to the rear of a prime mover11 and employing a row following system 12 coupled to a tool bar 13. Thetool bar 13 has shanks 14 carrying tools 15. As the cultivator movesforward, the tool bar 13 is prone to drift right or left as indicated bythe arrows 16 in FIG. 2. In order to correct this drift, sensors areused to feel the crop or the bottom of the furrow behind the tool barand any deviation from the desired position is corrected by the rowfollowing system.

In order to correct the position of the tool bar 13, the presentinvention employs a pair of frame members 17 and 18 which are secured tothe tool bar via vertical pivots 19 and 20. The frame members 17 and 18are constrained to remain parallel by a cross member 21 which ispivotally coupled to the frame members 17 and 18 at vertical pivots 22and 23.

Each of the frame members 17 and 18 include dog leg sections 24 and 25so that ends 26 and 27 of the frame members 17 and 18 project behind thecross member 21 in order to support respective hydraulic cylinderassemblies 28 and 29. Coulter wheels 30 and 31 are non steerable and inthis regard are fixed to rotate about an axis set at 90° to thelongitudinal axis of the frame members 17 and 18.

It will be appreciated, that whenever the cylinder assemblies 28 and 29are actuated to push the end portion 26 and pull the end portion 27 orvice-versa, then because the coulter wheels 30 and 31 are anchored inthe soil, the parallel frame members will bring about a repositioning ofthe tool bar 13 as the cultivator moves forward.

It will be appreciated that the present invention provides an immediateresponse with the force delivered by the hydraulic cylinder assemblies28 and 29 being delivered directly to the tool bar through the framemembers 17 and 18.

Referring now to FIGS. 3 and 4, there is illustrated a tool 40 for a rowcultivator, the tool being secured to a shank 41 (similar to the shank14 illustrated in FIG. 1) by a pair of plates 42 and 43 with the toolhaving a leading blade. In this case, the leading blade is aconventional sweep 44 which is mounted on a sweep attachment portioncomprising plate section 45 and 46 of the plates 42 and 43. The sweep 44is followed by respective blades 47 and 48 which have cutting edges 49and 50 extending rearwardly and outwardly behind the sweep 44. Theblades 47 are adapted to travel just below soil level in order to severroots outside the sweep 44.

The plates 42 and 43 are pivotally mounted on the shank so that theinclination of the blades can be adjusted or the plates 42 and 43 can beadjusted to suit different leading blades. For example an "Alabama" orother blade can be used as the leading blade.

The plates 42 and 43 include rearwardly extending ear sections 51 and 52receiving an upright portion 53 of a T-shaped plate which include wingsections 54 and 55 which hold the blades 47 and 48.

Blades 47 and 48 include leading edge portions 56 and 57 disposed withinthe periphery of the sweep 44.

The blades and sweep can be tilted as desired.

Referring now to FIGS. 5 to 7, there is illustrated a tool and shankarrangement using a shear release assembly according to the presentimprovement.

As can be seen in FIG. 5, there is illustrated a tool 60 disposed on thelower end of a shank 61 (similar to the shank 14 of FIG. 1). The shankbeing retained in a clamp 62 employing U-shaped clamp plates 63 and 64,the clamp being coupled to a tool bar 65 about a horizontal pivot axis66 on flange 67. The C-shaped clamp plate 63 includes a flange 68 whichabuts against a flange 69 extending down from the tool bar 65. Afastener in the form of a bolt 70 passes through holes in the flanges 68and 69 and secures the plate 63 to the tool bar 65, the bolt beingcentrally disposed relative to the plates 63 and 64.

As soon as the tool 60 strikes an underground object, the bolt 70 failsas illustrated in FIG. 6. Most usually, the bolt 70 will fail by thehead 71 breaking off or the nut 72 striping the thread.

It will be appreciated that by having the fastener in the form of a bolt70, that the fastening force holding the shank in place, extends in thedirection of travel of the tool and when the fastener 70 fails, thefastener 70 is easily removed during a short period of time. A newfastener can be put in place, and the shank returned to the positionillustrated in FIG. 5.

Whilst the above has been given by way of illustrative example of thepresent invention, many variations and modifications thereto will beapparent to those skilled in the art without departing from the broadambit and scope of the invention as herein set forth in the appendedclaims.

The claims defining the invention are as follows:
 1. A tool for a rowcultivator, the tool comprising:an elongated shank having an upper shanksection and a bifurcated lower shank section pivotally coupled to theupper shank section, the lower shank section comprising leading bladeattachment means projecting in a forward direction from the shank, and aplurality of cutting blade attachment means physically separated fromthe leading blade attachment means in a rearward direction from theleading blade attachment means; a leading blade for cultivating afurrow, said leading blade being mounted to the leading blade attachmentmeans of said shank, and having a rear end; and a pair of cuttingblades, adaptable to travel just below a soil level to sever weeds oneither side of the leading blade, the pair of cutting blades havingrespective forward ends and leading edges diverging rearwardly andoutwardly on opposite sides of a line passing through the leading blade,and being secured to respective cutting blade attachment means such thatthe rear end of the leading blade is physically separated fromrespective front ends of the cutting blades.
 2. A tool according toclaim 1, wherein the tool includes a blade carrier unit secured to theshank, the carrier unit having a forward leading blade attachment meansand a rearward cutting blade attachment means, the rearward cuttingblade attachment means comprising a pair of spaced vertical platesreceiving a cutting blade carrier unit in the form of an invertedgenerally T-shaped plate.
 3. A tool according to claim 2, wherein eachcutting blade is tapered, having a broad forward cutting edge portionlocated behind and inside a periphery of the leading blade.
 4. A toolaccording to claim 2, wherein each cutting blade has a forward portionlocated within a shadow of the leading blade.
 5. A tool according toclaim 2, including means for changing an inclination of the blades.
 6. Atool according to claim 1, wherein each cutting blade is tapered, havinga broad forward cutting edge portion located behind and inside aperiphery of the leading blade.
 7. A tool according to claim 1, whereineach cutting blade has a forward portion located within a shadow of theleading blade.
 8. A tool according to claim 1, including means forchanging an inclination of the blades.